Complex spirocyclic esters of boric acid



United States Patent 3,267,126 COMPLEX SPIROCYCLIC ESTERS 0F BORIC ACID Theodor Weil, New Brunswick, N.J., assignor to FMC Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 8, 1962, Ser. No. 236,392 Claims. (Cl. 260-462) This invention relates to novel esters of boric acid and, in particular, it relates to novels spirocyclic complexes of boric acid.

Simple boric acid esters have not been previously useful in many applications because of their susceptibility to moisture. They decompose so easily by hydrolysis to .boric acid and the alcohol that they cannot be used where moisture is present to cause hydrolysis.

I have discovered a novel class of hydrolytically stable, spirocyclic boric acid complex esters containing tetracoordinated boron. These novel non-polymeric esters have the formula Hal OH2O 0 Z GH2O 0 wherein Z is lower alkyl and M is selected from the group consisting of a substituted ethylene group, trimethylene group or aromatic ring in which the oxygen atoms are connected to adjacent carbon atoms.

Preferably, M has the following substituents: when M is an ethylene group of the formula R2 R1 R may each be hydrogen, alkyl, aryl, and R may be hydrogen, alkyl, aryl, allooxyalkyl, alkienyloxyalkyl,

R and R may each be hydrogen or alkyl, and R may be hydrogen, alkyl, alkenyloxyalkyl, alkoxyalkyl, or R4 and R may be joined in a heter-ocyclic group; and when M is an aromatic group of the formula I Rs R may each be hydrogen or lower alkyl. These borate complexes are useful as fungicides and bactericides, and they have surprising stability, even in the presence of water.

My new boric acid compounds are prepared by the reaction between boric acid or boric anhydride, a 1,2- or 3,267,126 Patented August 16, 1966 1,3-diol, and a Z-amino-Z-alloyl-lfipropanediol. The condensation reaction causes the splitting off of three moles of water per mole of product. The reaction can either be performed by combining all three reactants in an inert liquid medium and heating to the reaction temperature or in a stepwise fashion by first reacting the boron compound with one of the diols, thereby separating off two moles of water for each mole of the intermediate condensate, then adding the second diol and removing the third mole of water.

The reactants can be combined in any manner described above in an inert organic solvent, and it is even sometimes desirable first to dissolve the reactants in water. The reaction will go to completion readily when all the water present in the system either formed in the condensation reaction or added for the purpose of dilution is removed. The reaction may be conducted at an elevated temperature or under any conditions which will enable the water to be distilled off, and it is continued until three moles of water is formed for each mole of product. Preferably, water is continually removed throughout the entire reaction. The reaction will proceed at room temperature in inert solvent, in which case no water need be removed. However, the reaction time will be longer than at elevated temperatures. Upon completion of the reaction, the final non-polymeric product is a crystal.

Surprisingly, the amine-boric acid intermediate condensate will not react with a monohydric alcohol. In order to obtain my stable complex esters, the alcohol reactant must be dihydric. The reaction sequence is as follows:

REACTION 1 H2N CHr-OH HO o 13-011 z or-n-orr no Hu or-n-o 13-6 21120 Z/ \CH2-O REACTION 2 Hu CHz-O HO o /B-0 /M A OH2O HO ail o1n-o 0 13 M+nio z CHz-O 0 wherein Z and M have the scope previously assigned. The reaction sequence may be changed by adding the diol prior to the aminodiol, or together with it.

Removal of the water can be performed in a number or different known ways. A common method of Water removal is by azeotropic distillation during the reaction using a Water-immiscible liquid carrier for the reaction. Suitable azeotrope-forming solvents include chloroform, hexane, heptane, benzene, methylene chloride, or other inert, organic liquids. The azeotrope mixture can be readily separated, for example, in a Dean-Stark apparatus, and the solvent can be returned to the reaction vessel. The reaction temperature should be below about C.

'3 Q As stated above, either boric acid or boric anhydride may be employed at one of the reactants. Only half a mole of the anhydride is needed as shown below:

REACTION 1a CH2-OH Reaction 2 will be the same as Reaction 2 above.

My amine reactants are the 2-arnino-2-alkyl-1,3-propanediols. Preferably, the alkyl radicals are methyl and ethyl.

It is just as suitable to react the boron compound with the second diol prior to adding the amino compound.

"In that case, the intermediate will be Example 1 A mixture of 29.7 grams (0.250 mole) of 2-amino42- ethyl-1,3-propanediol and 15.46 grams (0.250 mole) of boric acid in 500 ml. of chloroform were heated to reflux on a steam bath. The water-chloroform azeotrope which distilled 011 was separated in a Dean-Stark trap. When about 8 ml. of H 0 had been collected, a precipitate formed. The yield of boron-aminodiol intermediate was quantitative.

AnaL-Oalc. for C H O NB: C, 41.42; H, 8.34. Found: C, 40.23; H, 9.07.

Example 2 A mixture of 52 grams (0.5 mole) of neopentyl glycol, 26.3 grams (0.5 mole) of Z-amino-Z-methyl-l,3-propanediol and 30.9 grams (0.5 mole) of boric acid were dissolved in ml. of water in a 3-necked flask equipped with a Dean-Stark distillation trap. The mixture was heated slowly until a completely clear solution was obtained. Then 300 ml. of heptane were added and the mixture heated on a steam bath. Approximately 25 ml. of water was collected in the trap. A precipitate formed at the end of the reaction. This solid matter was filtered off, washed with ether, and dried. The yield of this crystalline precipitate was 100 grams (92.6% of theoretical).

Anal.Calc. for C H O NB: C, 49.80; H, 9.24. Found: C, 49.41; N, 9.51.

An almost identical product was obtained by stirring the above reactants in ether for 24 hours at room temperature.

Example 3 Example 4 The tables below list compounds prepared by reacting;

boric acid or anhydride, 2-amino-2-methyland Z-amino- 2-ethyl-1,3-propanediol and various diols together using the methods employed in the above examples. These tables are arranged by listing the diols used. The formula and elemental analyses of each borate ester are included.

A. ESTERS PREPARED WITH 2-AMINO-2-METHYL-l,3-PROPANEDIOL Analysis Diol Formula C H N B Cale. Found Cale Found Cale. Found Cale. Found Ethylene glycol CsH14O4NB 41. 18 39. 84 8. 06 8. 40 8. 00 7. 63 6. 18 5. 98 1,2-propanediol. C7HwO4NB 44. 48 43. 25 8. 53 8. 77 7. 41 6. 71 5. 72 5. 37 1,3-pr0panedi0l. C1H1tO4NB 7. 41 7. 72 5. 72 5. 40 2,3-butanedioL CaH1aO4NBH 47. 32 45. 62 8. 94 9. 05 6. 09 6. 94 5. 33 5. 51 Monoacetin CaH1aOuNB 43. 74 43. 91 7. 35 7. 80 PyrocatechoL CmHuO-iNB 53. 86 52. 51 6. 33 6. 81 6. 28 5. 99 4. 4. 71 2-1nethyl-2,4-pentanediol C1 H 2O4NB 51. 97 53. 31 9. 60 9. 99 6. 06 6. 35 4. 68 4. 46 Pinacol C10H2204NB 51. 97 51. 66 9. 60 9. 38 6. 06 6. 15 4. 68 4. 72 2,2-dimethy1-1,8-butanediol- C1nH22O4NB 51. 97 52. 07 9. 60 9. 89 6. 06 6. 09 4. 68 4. 48 2,2-diethyl-1,3-propanediol C11Hz4O4NB 53. 91 53. 97 9. 81 10. 10 5. 72 6. 33 4. 42 5. 34 2-tg hi l-2-allyloxy-methyl-l,3-propaueolaHzfiosNB 54. 37 53. 85 9. 13

1o 3-(O-to1yloxy)1,2-propanediol C14H2205NB 56. 97 57. 67 7. 52 2-phenyl-oxazoline-4,4-dimethanol C15H24O5N2B 3. 20 Benzopinaeol C3uHa0 4NB 75. 16 73. 25 6. 31 2. 94

B. ESTE RS PREPARED WITH 2-AMINO-2-ETHYL-1,3-PROPANEDIOL C H N B Diol Formula Oalc. Found Cale. Found Calc. Found Calc. Found Ethylene glycol 01H 16O4NB 44. 48 43. 82 8. 53 8. 74 Neopentyl glycol Clfl1I2204NB 51.97 50. 9. 60 9. 54 6. 06 6. 53 4. 68 4. 58

Example 5 To show the utility of these compounds, several esters were prepared according to the procedure of Example 1 with different diols as listed below. The compounds were 5 then tested for fungicidal effect on Aspergillus niger, Pullularia pullulans, Penicillium expanszmz and Alternaria solani. They were also tested for effectiveness in killing Bacillus mycoz'des and Aerobacler aerogenes.

FUNGICIDAL AND BACTERICIDAL TESTS OF BORIC ACID ESTERS WITH DIFFERENT DIOLS AND 2-AMINO-2-METHYL-1,3-PROPANEDIOL Fungieidal Tests Diols Bactericidal Tests Pen. expansum A. niger P.

pullulans Alt. solam' A. mycoides Aerogenes Neopentyl glycol, mm Ethylene glycol, mm 1,2pr0panediol, nun Pyroeatechol, man. 2,3-butanediol, min 2,2-dimetl1yl-1,3-butanediol, mm. 2-n1ethyl-2,4-pentauediol, mm l 1,3-pr0panediol, mm Pinacol, mm

1 No inhibition. 3 Complete inhibition.-

The above results were obtained by placing 0.25 gram of the test compound inside a ring of l2 ml. inside diameter drawn in the center of a plate containing fungus or bacterial cultures. The fungus culture was incubated at C. for 72 hours; the bacteria culture was incubated at 37 C. from 24-36 hours. After incubation, if a clear Zone resulted showing that the organism did not grow, the test compound was reported as toxic to the organism. The distance of the clear zone from the nearest culture growth to the center of the ring was measured and reported; for example, a non-toxic specimen or blank standard would have a measurement of zero or no inhibition. The amino-boric acid intermediate also has fungicidal and bactericidal activity. Using the same test method as above, the following results were obtained with the 2- amino-2-methylpropanediol-boric acid intermediate compound:

A. niger -mm 8 P. pullularls mm 10 Pen. expo/1mm rnm 14 Alt. solani No inhibition B. mycoides mm 8 A. iaerogenes mm 8 The boric acid esters prepared herein are not only stable to hydrolysis, but are also water-soluble, and they may conveniently be applied as a pesticide in a water solution as well as in an inert organic solvent.

Having fully described my invention, I claim:

1. A spirocyclic borate ester of the formula H3N CHPO B M CH2O O in which Z is hydrogen or lower alkyl and M is in which R and R are hydrogen or lower-alkyl, R is hydrogen, lower-alkyl, allyloxy-lower-alkyl or lower-alkoxy-lower-alkyl, and R and R may be joined to form a Z-phenyl-oxazoline-4,4-radical, or

(c) an arylene group of the formula in which R is hydrogen, lower-alkyl or mercapto.

2. A spirocyclic borate ester of claim l in which M is an ethylene group of Formula a.

3. A spirocyclic borate ester of claim l in which M is a trimethylene group of Formula b.

4. A spirocyclic borate ester of claim l in which M is an arylene group of Formula 0.

5. A spirocyclic borate ester of the formula wherein Z is methyl or ethyl.

6. A spirocyclic borate ester of the formula wherein Z is methyl or ethyl.

7. A spirocyclic borate ester of the formula 8. A spirocyclic borate ester of the formula 9. A spirocyclic borate ester of the formula 10. A cyclic borate ester having the formula wherein Z is a lower alkyl radical.

References Cited by the Examiner UNITED CHARLES E. PARKER, Primary Examiner.

NICHOLAS RIZZO, Examiner.

ALTON D. ROLLINS, DELBERT R. PHILLIPS,

Assistant Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,267,126 1 August 16, 1966 Theodor Weil It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 10, for "novels" read novel column 3, line 2, for "at" read as line 41, for "29.7" read 29.74 columns 3 and 4, table A, under the heading "N", line 4 thereof, for "6.09" read 6.90

Signed and sealed this 1st day of August 1967.

(SEAL) Attest:

EDWARD M. FLETCHER, JR.

Attesting Officer EDWARD J. BRENNER Commissioner of Patents 

1. A SPIROCYCLIC BORATE ESTER OF THE FORMULA
 10. A CYCLIC BORATE ESTER HAVING THE FORMULA 